Update paper.md

Author: PStange

paper/paper.md

@@ -49,7 +49,8 @@ Flixopt fills this gap by enabling:
 * full flexibility of system construction 
 * detailed representation of operational and investment behavior
 * arbitrary evaluation metrics through *Effects*, supporting multiobjective and constrained formulations. 
-* todo: dimensions scenario and period!
+* multi-year investment planning by using periods
+* seperate or combined consideration of scenarios within the optimization
 
 Flixopt is designed for flexible use across various disciplines and research questions or practical tasks ranging from operational dispatch to strategic planning.
 
@@ -91,7 +92,7 @@ Flixopt introduces a freely definable system of evaluation metrics called *Effec
 
 ## Scenarios and Periods 
 
-Periods typically refer to multi-year time segments within a long-term planning horizon. They are used to structure the model over several years (e.g., investment or transformation stages), allowing the representation of system evolution over time—such as capacity expansion, technology diffusion, or changing boundary conditions—while keeping the optimization problem tractable. Scenarios, in contrast, describe alternative assumptions about external developments or system configurations. They enable the structured comparison of different futures, such as varying fuel prices, policy settings, technology costs, or demand trajectories within a consistent modeling framework.
+Periods typically refer to multi-year time segments within a long-term planning horizon. They are used to structure the model over several years (e.g., investment or transformation stages), allowing the representation of system evolution over time, such as capacity expansion, technology diffusion, or changing boundary conditions, while keeping the optimization problem tractable. Scenarios, in contrast, describe alternative assumptions about external developments or system configurations. They enable the structured comparison of different futures, such as varying fuel prices, policy settings, technology costs, or demand trajectories within a consistent modeling framework.
 
 ## Acknowledgements